Large waterborne vehicles, such as cruise ships, cargo ships, military vessels, and the like are difficult and slow to maneuver. Narrow passageways and restricted waters can exacerbate the maneuvering difficulties by restricting the operable or navigable area of the vessel. In some instances, large ships may take up to several kilometers (i.e., a nautical mile or more) in order to complete a turn or come to a stop. Due to these difficulties in maneuvering such large ships, every year many ships run aground or make contact with hazards, which cause damage to the ship. In some cases, the ship, crew and cargo may all be lost if the ship sinks. In other instances, damage to the ship may cause environmental damage, such as oil spills or other pollutants being released to the air, land and water.
Further, in developing countries, waterways such as ports, harbors and rivers may be poorly maintained for large ship travel. For example, surveying and dredging is sporadic, and currents, tides and waves can cause rapid changes in the bottom contours of the waterways due to sedimentation and moving sandbars. Despite such conditions, many large ships still frequently travel on these poorly maintained waterways. As such, these ships may run aground or make contact with the bottom of the waterways, which causes damage to the ships and risks environmental destruction.
Some waterways such as bays, fjords, deltas, and rivers, are prone to transient local currents and eddies, and gusting wind. These can cause large ships to be driven off course, thereby running aground or into other hazards or obstructions.
In other areas, marine life is also a concern for ship traffic. For example, in some areas, endangered species, sleeping or nursing whales and the like may be injured or killed if they are run into by a ship. Further, impacts with such large marine mammals may cause damage to the ship.
In order to avoid collisions, ships typically rely on navigation charts to set up routes to avoid hazards and stay in waters deep enough for the ship's required draft. However, in many instances, the data on the navigation chart is inaccurate, incomplete or non-existent, thus requiring ships to enter some areas with extreme caution (e.g., excessive slowing of the ship's speed). Excessive slowing of the ship's speed may further reduce the maneuverability of the ship, and make the ship more vulnerable to attacks, such as by pirates.
In major ports, large ships are typically greeted outside the port by a local pilot who boards the ship and takes control for navigation and docking in the port. In some locations, the navigation and docking are further assisted by local tugboat operators. However, at many smaller ports, such assistance is not available and the ship's pilot must navigate and dock the ship without assistance. Such is often the case for restricted waters not associated with a major port, such as coastal areas, lakes, rivers and channels between islands. In order to navigate in these areas, most ships measure water depth directly below it using an echo sounder. However, few ships are equipped with any device that can measure the bottom contours ahead of the ship. In either instance, the effective range of the bottom contour measurement is too short to allow sufficient distance for the ship to make evasive maneuvers around unexpected underwater hazards. For above-ground hazards, some ships may be equipped with a radar system, but radar systems are limited to line-of-sight, and are not effective to “see” around points, bluffs, or man-made structures, which may be required when navigating in fjords, rivers, bays, rugged coastlines, or the like. Other surface objects and debris may be avoided by careful observation by the ship's crew, but many hazards, such as currents, eddies, and gusting wind are difficult to detect with the unaided eye, and thus are not noticed until it is too late for the ship to make an evasive maneuver.
In some areas, international laws place regulations on ships to comply with low speed requirements in certain areas, for example in seasons and areas known for whale feeding and breeding. However, such restrictions do not always prevent ships from colliding with the whales. In some cases, ships do not comply with the speed requirements because of operational limits such as maneuverability, engine, or time constraints, thus placing the ships and wildlife at risk for collisions.
Thus, a need exists for a navigation and hazard avoidance system that addresses the above issues.